Zora's Fountain

When you're back outside again, Ruto will give you Zora's Sapphire, the last
Spiritual Stone! After you get the last Spiritual Stone, head to Hyrule
Castle to tell Zelda. When you get there, Gannondorf has come and Zelda has
been taken from the castle with Impa. She'll drop the Ocarina of Time in the
stream around the castle, so after the scene is over and you can move, dive
into the water to get it. Once you get it, it will teach you the Song of
Time. Now, enter the Market and head to the Temple of Time.